cystathioninemia /sis′təthī′əninē″mē·ə/ , an inherited metabolic disorder, caused by a deficiency of the enzyme cystathionase, that causes an excess of the amino acid methionine. Some patients are asymptomatic, whereas others show signs of cognitive impairment, as well as thrombocytopenia and acidosis. It is treated with large doses of pyridoxine (vitamin B6).
